IntroductionThe reasons I made this review of the HVL-F42AM are: 1) I wanted to practise and see whether I would be capable of reviewing the A700 with Carl Zeiss 16-80mm lens; 2) I thought it would be useful for those who do not have an external flash yet. Beware that I am nowhere near a professional photographer and that I've only had this flash for about a month or two. My goal is to show what an external flash can offer and I will mostly compare it to the build-in flash of the Sony Alpha 700.

DesignI couldn't compare the HVL-F42AM flash to any other flashes, but something that I noticed is the fact that the flash is very clean, there are not too many buttons and switches on it. On the left side of the flash, you'll find a button to release the flash from the camera. On the right side, there's a door to the battery compartment which holds four AA batteries, either Alkaline or Nickel hydride. I bought some GP ReCyKo+ batteries, and I'd recommend these to everybody. They last up to 4x as long as Alkaline batteries and you can recharge them up to a 1000 times.

The front of the flash shows nothing but the Sony logo, an AF illuminator and a sensor for wireless shooting, which I'll write more about later. The back of the flash has most buttons, which you can see in the image below:

Underneath the screen there's a Mode-button (Flash off, Auto, Wireless with two channels), an HSS-button (so you can shoot with shorter shutter times than the usual 1/250th of a second), a Level-button (select the power of the flash: 1/1, 1/2, 1/4, 1/8, 1/16, 1/32 and Auto) and a Zoom-button (select focal length (105, 70, 50, 35, 28, 24, wide (up to 16) or Auto). When you use a focal length of, say, 16mm (24mm equiv.), the indicator Wide on the screen will start flashing, letting you know you have to pull the diffuser out. (see how it works in this video). This diffuser works very well and reduces dark edges as seen in the images below:

Without the diffuser:

With the diffuser:

The screen itself shows all the indicators that belong with the buttons, plus a battery indicator that only flashes when the batteries are about to run out. This is one of the downsides of the flash, since it's always a surprise when you have to replace the batteries. The last button on the flash is a Test-button, this will make the flash fire once. Other flashes of Nikon for example, will fire lots of soft flashes in a row to allow you to see the effect of the flash through the viewfinder. Why Sony chose only one flash I don't know, but it certainly isn’t as helpful as Nikons method.

One of the reasons I chose this flash, and not the cheaper HVL-F36AM, is (apart from the difference in guide number) the fact that this flash had a moving head. You can tilt the head upwards by either 45, 60, 75 or 90 degrees, to the left by 30, 45, 60, 75 or 90 degrees, and to the right by 30, 45, 60, 75 or 90, 120, 150, 180 degrees. This means you can bounce of walls and ceilings, one of the greatest advantages of an external flash. This is most useful for portraits, since your subject will not be blinded by the light of your flash and because the light reflected of a wall is much softer. The next picture shows this effect:

I uploaded a short video on YouTube to show how the head of the flash can move.
In this video, you’ll get some general impressions of the flash and I’ll show what the buttons are for.

Advantages over the build-in flashOne of the most important features of the flash I’ve already described, the moving flash-head. There are however more features that are very useful. One of the most important ones is power. The build-in flash of the Alpha 700 has a guide number of 12, which may be sufficient for many situations, but will sometimes not be enough. The HVL-F42AM has a guide number of 42, which is a lot more versatile. The reach of the flash is much longer and this will allow you to illuminate your subject better. The image below was taken outside, with almost no other light than the flash, from quite a distance away. These are some of my classmates and they were shocked by the power of the flash, some of them were blinded a little.

Another really neat feature of the HVL-F42AM flash is the HSS-mode (High Speed Synchronisation). This allows you to use shorter shutter times. The build-in flash’ minimum is 1/250th of a second (1/200th with SSS on). With HSS you can use shorter exposure times, so you can freeze the action or get some creative effect you’re looking for. This feature is really useful if you’re making a portrait outside, with plenty of sunlight, but you just want to get rid of the shadows on your model. If you’d use the build-in flash, you couldn’t use a shorter shutter time than 1/250th of a second, so you’d have to close the aperture somewhat. This would make your DoF larger and the background would be sharper, which is not always good for your portrait. With HSS on, you can select a shorter shutter time, and get the kind of image you want.

The HVL-F42AM also allows you to flash manually. This is mainly useful in low light situations, where you want to lighten up the foreground a little. You can use the Test-button to fire the flash while using a long shutter time. With this feature, you can also make the same person/object appear in your photo multiple times, by flashing several times during your exposure and moving the subject after every flash.

One of the greatest advantages of the HVL-F42AM flash, however, is its ability to flash wirelessly. The way this works is simple. You put both the camera and the flash in wireless mode, flip up the build-in flash, position the external flash where you want to and take the photo. The build-in flash will fire once, sending a signal to the external flash’ sensor, which will then fire too. With this feature, you can achieve special looking light effects and other creative effects that will probably improve your picture. Sony provides a nice little mini-stand to position your flash where you want to, and this stand can also be mounted on a tripod (!). The following picture was taken with the external flash on the right side of the subject:

You might be thinking: You could also bounce the light to get that effect, right? Which is true. But sometimes the walls/ceilings are to far away to produce a correct exposure, and the flash will use it’s maximum power to illuminate the photo as good as possible, which will drain your batteries. Also, by bouncing, the flashlight becomes softer, which you may not want.

The last feature of the external flash I’d like to tell about is its speed. The build-in flash fires at a slow rate, but the HVL-F42AM can fire up to 40 flashes at a rate of 5 flashes per second. This is at its lowest power setting though, but even at higher settings, the flash is very fast and you can still do good continuous shooting. The power-up-time of an external flash is also very fast.

If you want to see the difference in speed of both the build-in flash and the HVL-F42AM, click on the links and watch a YouTube video.

ConclusionI think it’s definitely worth the money to buy an external flash, because it will offer you much greater freedom in photography. The HVL-F42AM has become my favourite addition to the Alpha 700 and will remain in that position till I buy a 70-200 F2.8G SSM lens .
I hope some of you found this review useful, please tell me if you did. Also, if you have any questions or remarks, please leave a message.

Special thanks to Gordon Laing, who inspired me to make this review.

Note:I tried to avoid making mistakes as much as possible, but there may still be some. Sorry for the inconvenience.

Thanks Bob!
BTW, it's my intention to compete with Gordon; he inspired me to do this, so I had to include some videos too.
When I get my 70-200 F2.8G SSM (hopefully by the end of this year), I'll see whether I can review that too.

What about comparing to other products a DSLR user might consider, while on a budget? E.g. pros of buying a flash over another lens.

This depends mostly on the kind of photography you like to do. If you into nature- or wildlife photography, an extra lens is to be recommended. If you portraits, both a flash and a lens would be nice. The flash is very useful for those who like or have to shoot inside, or in dark light.

The reason I chose to buy the flash and not an extra lens, is because I was about to go to Finland, and I saw from last year's photos that we'd spend quite sometime inside, and then it's very useful to have a flash. Also, I could afford this flash and not a telephoto zoom yet.

There are of course times when you'd rather have an extra lens than a flash. Yesterday I went to the Apenheul, a sort of zoo here in the Netherlands, with lots of monkeys (apen). Some of them are not in cages and you can touch them (not allowed though). With a telephoto zoom like the 70-200 (which I'm saving for), or a 70-300 would have been very useful there.
For other situations, like portrait photography, a 50mm F1.4 prime would be very useful, possibly more useful than a flash.

So you have to weigh up the advantages that a flash offers, and those that the lens you'd like offers, and choose whichever seems most useful to you, you should buy. I wouldn't recommend the flash over a lens, because both can be really useful.

- Bjorn -

If this part of text contains some mistakes, I was listening to a new CD while typing

I was thinking about buying a flash, and after reading your review last week, I desided to get this one!

It's indeed a very good flash, and it really opens up a new world of creativity. I'm particularly amazed by the simplicity of how you can control the light when using the flash in wireless mode. Most of the time the metering is correct, and you don't have to use flash compensation.

Thanks for the review that gave a good overview of the possibilities.
I never heard from HSS before, but this is also an amazing feature.
(Today I shot my avator picture on the left with a shutter speed of 1/1000 of a second, while I hold the flash myself.)
Where I was able before to throw the background out of focus with large apertures, I can now throw the background completely out with this...

As long as what you have told me is true :P I really hope it can. (Tilted head and wireless)

It's really all the info that I needed to purchase the thing. I want to use the flash that way, especially in self portraits, but I shall say no more. i have $20 in coupons.... and.. $70 cash $300 - $90 = $210 :( plus tax.

As long as what you have told me is true I really hope it can. (Tilted head and wireless)

Of course it's true, why would I lie to a CL member? There's a video which shows how the flash head moves here (uploaded by myself).

I did some wireless flash-photography this morning, and it works great. The lighting that you can achieve by positioning the flash on the side of your subject is great. If you want me too, I could upload an example photo. The one in the review was deleted by mistake from Flickr...